The word "density" has become the rallying cry of the no growth xenophobes in our nation's cities and neighborhoods. It is an all-purpose scare tactic used to stop land use and transportation projects. But why do people react so negatively to the word? What is the pathology of density?
The Genetic Code: One answer is that our reaction to human density has more to do with our evolutionary genetic programming than with our conscious analytical thought. Carl Sagan and Ann Druyan, in their book Shadows of Forgotten Ancestors, make a compelling argument that human behavior is the result of 500 million years of DNA programming and the process of natural selection. They say that for some primates, "If population density becomes too high, then mechanisms are set into motion to reduce it." These forces may include, "...fighting and domestic violence, child abuse and neglect, soaring infant and maternal mortality; psychosis... gay bashing; alienation, social disorientation and rootlessness..." Two Theories of Density: Jane Jacobs, in The Death and Life of Great American Cities, says that using persons-per-acre is a "statistical monstrosity" because it masks the real problem of overcrowding. She argues that higher density may or may not result in overcrowding -- or too many people per room -- which is the real culprit destroying urban livability. Jacobs argues for increased density linked to increased livability. The theory being that if you give people the idyllic new urbanist neighborhood, with espresso bars and boutiques, then they won't care how dense their neighborhood is. Ian McHarg, the guru of ecological planning, in his book Design With Nature talks about a "pathological togetherness" where as "density increases, so do social pressures, which manifest themselves in stress disease..." He basically agrees with Sagan and Druyan, and cites the same studies. He says the evolutionary reason for this pathological behavior is that "stress inhibits population growth." It is nature's way of fighting increased density. McHarg appears to disagree with Jacobs and concludes that of all the urban stress factors "the single obvious one is not poverty, but density..."
Cultural Norms: One of the most dense human populations on earth exists in Hong Kong. Everyone lives in concrete towers and the average density is 280,350 people per square mile. If high density carries with it such a negative pathology; then we must ask ourselves why crime is so low there. Part of the answer is cultural. Hong Kong has a unique British-Chinese tradition that produces a high standard of living, an unusual civility and a respect for authority. So the pathology of density may have a threshold governed by more than genetic programming and spatial density. It may also be governed by regionalized cultural norms that are important to understand. For example, if there is any human population totally ill suited to higher densities, it is people living in the American West. Their ancestors originally came West to be free of the overcrowding in the Eastern cities and in some cases to be free from authority and society. These independent characteristics (and characters) are an inherent part of their cultural fabric and their value system. Political motives. Environmental activists -- who are often allies with the no growth advocates and see development as the common enemy -- have completely different motives regarding density. Some environmentalists would like to take a perfectly good idea like "smart growth" to a political, social and economic extreme. Their strategy is greatly increase urban density in order to save the natural environment. This would be achieved by packing people into dense human reservations and limiting their mobility by convincing them that they don't need automobiles.
Towards a Better Model: It is time that we planners reconsider dictating unrealistic and artificially high density targets. A more rational approach is to let cities design and build neighborhoods at densities that the residents actually want to live in. We can still create a compact urban growth form that optimize both the land use settlement pattern and our infrastructure delivery costs. We also need to realize that market demand changes over time with population demographic, so we should adjust the density mix. This approach will go a long way in reestablishing the local voter's faith in our planning efforts.
Richard H. Carson is a writer and planning director who lives in the Pacific Northwest, and former elected official of the American Planning Association (APA). He currently maintains APA's "Internet Planning Media" and the independent "About Planning" websites.